1. Field of the Invention
The present invention generally relates to closed loop single shot multivibrators and, more particularly, to those employing delay circuits connected between inverting logic circuits within the loop for controlling output pulse width.
2. Description of the Prior Art
Closed loop multivibrators are known in which a delay circuit, connected between two inverting OR circuits or between two NAND circuits within the loop, determines the output pulse width as well as the recovery time. An example of the former is given on page 262 of "Manual of Logic Circuits", G. A. Maley, Prentice Hall, 1970. The latter is shown in exemplary U.S. Pat. No. 3,601,636, issued to L. W. Marsh, Jr., on Aug. 24, 1971 and entitled Single-Shot Device.
For proper operation, the input pulse to the cited multivibrators must be inactive ("down" for the inverting OR case) for a length of time greater than the delay of the delay circuit and the input pulse width must be greater than the delay of the two inverting OR circuits or NAND circuits, as the case may be. If the input pulse cycle time is too short and does not meet the first of the two foregoing requirements, recovery of the multivibrator is incomplete with the consequence that the output pulse width becomes foreshortened and is less than the delay of the delay circuit.
It is desirable, for certain system applications, that the recovery time of the multivibrator be reduced below the delay of the delay network in such a way that corresponding reduction of the output pulse width is avoided.